The monument consists of a small, roofless chamber formed by three standing stones; a backstone at the east-southeast end and two opposing sidestones that create a space roughly 1.5 metres long. The chamber narrows from 1.7 metres at its open west-northwest entrance to 1.1 metres at the back. Several displaced slabs lie scattered about, including a substantial one resting against the southern sidestone that may have once served as a portal stone. The entire structure sits within a low, grass-covered mound measuring 5.7 by 4.2 metres, though much of this appears to be accumulated field clearance rather than original construction.

The monument’s exact classification remains a mystery. Initially catalogued as a portal tomb due to its single chamber facing uphill, subsequent surveys have been less certain. The possibility exists that what remains visible today represents only a fragment of a once larger megalithic structure. Without clear diagnostic features, archaeologists have ultimately listed it as unclassified, leaving its original purpose and full extent open to speculation.

Despite its modest appearance and remote location, unmarked on any Ordnance Survey maps, the site offers commanding views across Lough Swilly to the east. The surrounding landscape of County Donegal holds numerous megalithic tombs, each contributing to our understanding of prehistoric Ireland, though this particular example at Lisnanees Upper guards its secrets particularly well. First documented in the 1840s, it has since appeared in various archaeological surveys, most notably in Eamon Cody’s comprehensive Survey of the Megalithic Tombs of Ireland, where its ambiguous nature continues to intrigue researchers.